Integral universal stretcher bar

ABSTRACT

A stretcher mechanism for canvas consisting of a substantially rectangular base member and a flap secured to each side of the base member by a living hinge. The canvas is secured to the flaps and the flaps are pivoted about their hinges through a segment of an arc, thereby causing the canvas to be placed under equal tension in four directions.

United States Patent Campione June 3, 1975 1 1 INTEGRAL UNIVERSAL STRETCHER BAR [76] Inventor: Joseph C. Campione, l 156 Wilcox Ave., Monterey Park, Calif. 91745 [22] Filed: Apr. 23, 1973 [21] Appl. No.: 353,693

52 use; USO/374.1; 38/l02.91 511 Int. Cl ..B44d 3/18 581 Field of Search l60/374.1, 378, 330, 135;

[56] References Cited UNITED STATES PATENTS 10/1937 Riley 16/150 3/1966 Munn 160/3741 3,273,497 9/1966 Rosema el al. 160/378 X 3,477,574 11/1969 Malfroy 160/378 X 3,559.316 2/1971 Galper 160/378 X 3,662,807 5/1972 Miller 160/135 Primary E.\'aminer-Philip C. Kannan Attorney, Agent, or Firm-Matthew P. Lynch 5 7 ABSTRACT A stretcher mechanism for canvas consisting of a substantially rectangular base member and a flap secured to each side of the base member by a living hinge. The canvas is secured to the flaps and the flaps are pivoted about their hinges through a segment of an are, thereby causing the canvas to be placed under equal tension in four directions.

4 Claims, 10 Drawing Figures WERNER Juzz 3 1975 SHEET qag- INTEGRAL UNIVERSAL STRETCI-IER BAR BACKGROUND OF THE INVENTION Originals of masterworks of art, such as oil paintings and the like, can obviously be owned by very few individuals. Accordingly, the masses of art lovers are able to own the master-works only in the form of mechanical reproductions thereof, such as prints and the like. It is generally recognized, however, that even the finest of mechanical reproductions cannot give the satisfaction, or take the place of, an original painting. Moreover, the pleasure derived from ownership of an original painting, despite the fact that the same may comprise the work of an unknown artist cannot usually be satisfied by a mere reproduction. Thus, there has been a growing demand in recent years for original paintings.

In order to satisfy the aforementioned demand for original paintings, it is of course necessary to make such paintings commercially available at a price reasonable enough for most people to afford. Aside from the cost of the artists talents, one of the most important consideration in any scheme of massproduced original paintings is the time and expense required to prepare and mount the canvas before painting. In this regard, it is well known that the canvas must be properly stretched and mounted on some type of supporting framework, usually rectangular in shape.

Heretofore, the preparation and mounting of the canvas was accomplished by the artist in one of the following ways. Four cooperating wooden strip members were connected together with mitered corner joints to afford a rectangular open framework. These wooden members were usually formed with pairs of aligned slots adjacent the inner corners thereof. A piece of canvas was cut roughly to the size of the framework and the marginal edges thereof were nailed to the side edges of the frame members. It was then necessary to delicately tap wooden wedge blocks into the slots at all four corners in order to obtain the desired degree of tautness in the canvas. As many as eight such wedges were ordinarily needed. The described operation was not only time consuming, but also required considerable skill and judgment of the artist in tapping the wedge blocks into the corner slots to obtain the proper and uniform tautness over the entire surface of the canvas.

Another method was to construct the framework as set forth hereinabove and then staple one edge of the canvas to the back of one side of the framework. The artist then manually pulls the canvas taut over the opposite side and holds it in place while he staples that side, then the entire operation is repeated for the two remaining sides. This method obviously takes a greater degree of skill and time than the prior method since it is very difficult to correctly tension and space the canvas and avoid wrinkles while simultaneously stapling it.

A further method is to pre-cut the four cooperating wooden strip members with their mitered corner joints and additionally carefully cut the canvas to size and cut off the four corners diagonally, thereby forming four elongated hexagons along its sides, which hexagons consist of a narrow rectangular section and an isosceles trapezoidal section. The four wooden strips are then tacked to the outer isosceles trapezoidal section of the sides and rotated inwardly through an arc of 180 until the mitered corners abut and then the abutting corners of the strip members are stapled or joined together by any well known mechanical fastening means. This method has a number of obvious disadvantages, most important of which is that unless the wooden strips are secured to the canvas at exactly the right position and orientation, the mitered corners will not meet correctly and the forcing of the strips will cause the framework to warp and thereby cause wrinkles in the canvas.

All of the aforementioned methods of stretching canvas have inherent problems which require that they only be practiced by highly skilled and consequently highly paid artisans.

SUMMARY OF THE INVENTION The present invention overcomes the aforementioned problems by providing a stretcher bar that eliminates the need to employ skilled artisans in order to properly stretch a canvas for framing.

The stretcher bar or mechanism of the present in vention comprises a base member having a substantially rectangular configuration and a flap secured to each side of the base by a living hinge, whereby the flap is held in spaced complementary relationship to the base. A canvas is caused to be secured to the flap and the flap is then pivoted through a segment of an are about its hinge causing the canvas to be placed under tension and stretched to a drum-tight condition across the base member.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective of one embodiment of the invention.

FIG. 2 is a partially cut-away perspective of the invention in its assembled condition.

FIG. 3 is an enlarged sectional view of the stretcher mechanism.

FIG. 4 is a transverse cross-section of FIG. 2, showing in solid line the flaps in their open position and in dotted line their closed position.

FIG. 5 is a transverse cross-section of FIG. 2, showing in solid line the flap in its closed tension position.

FIG. 6 is a perspective view of an alternate embodiment of the invention.

FIG. 7 is an enlarged sectional view of the stretching flaps in their open position.

FIG. 8 is a transverse cross-section of the stretching frame.

FIG. 9 is an enlarged sectional view along line 9-9 of FIG. 8.

FIG. 10 is an enlarged sectional view of an alternate method of securing the flaps.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, wherein like reference numbers designate like or corresponding parts throughout the several views, there is shown in FIG. I an integrated stretcher mechanism 10. The stretcher mechanism 10 is adapted to become an integral part of frame I] and secure in a drum-tight condition thereto a canvas 12. The canvas 12 is shown with its corners clipped in order that the final stretched framed product will have a neat appearance without the canvas being bunched up in the corners; however, the clipping is not necessary for the successful operation of the invention.

The frame I1 is of a standard type having an opening 13 and a stepped cut-out portion 14 along the inner periphery of the opening 13. The cut-out portion 14 is adapted to receive the stretcher mechanism which can be secured therein by glue or other chemical or mechanical bonding means in a manner shown best in FIG. 3.

FIG. 3 is an enlarged view of the stretcher mechanism 10 in position on the frame 11, prior to the securing thereto of the canvas 12. The stretcher mechanism 10 has a base and a flap 16 which is secured to the base 15 in a manner hereinafter described. The base 15 consists of four wooden strips 19 having mitered complementary corner joints adapted to form a rectangular structure. Each of the strips 19 has a rectangular portion 17 coextensive with a trapazoidal portion 18, the portion 17 mating with the stepped cut-out 14 of the frame 11 and the trapazoidal portion 18 extending inwardly into the opening 13 along all four sides.

The flaps 16 are substantially rectangular in shape and are secured to the back side of the rectangular portion 17 of each of the strips 19 by a securing means 20 which has all the attributes of a living hinge. The securing means 20 may be constructed from any of a large number of flexible materials including, but not limited to, plastic, cloth and paper.

The securing means 20 is fastened along one end to the back side of the rectangular portion 17 of each of the strips 19 substantially along its entire length by any well known means, such as glue. The opposite free end of the securing means 20 is fastened along its free end to one side of the flap 16 so that the secured side of the flap 16 lies in spaced co-planar alignment with the back face of the base 15 and in substantially parallel spaced relationship to the back face of the frame 11. In order to facilitate the interconnection between the flaps 16 and the base 15, the securing means 20 may be constructed from two-sided adhesive tape, wherein both sides of the tape have an adhesive coating which during non-use is protected and covered by a peelable protective strip 21. The aforementioned two-sided adhesive tape is best illustrated in FIGS. 3 and 5, where it can be seen that in addition to being secured to the co-planar side of the flap 16, an additional strip is fastened to the opposite side thereof as indicated by numeral 22.

In assembly, the canvas 12 is laid on a flat surface with its painted side facing up, then the protective strip 21 is removed from the securing means 20, which serves the dual purpose of being both a hinge and a securing means. The frame 11, including the stretcher mechanism 10 is poitioned over the canvas 12 until the picture on the canvas is centered within the opening 13, then the frame 11 is set down upon the canvas and the canvas is thereby caused to adhere to the securing means. The frame 11, with the canvas held in position thereon, is then turned over and the protective strip 12, which overlaps and protects the strip of adhesive tape 22 on the opposite side of the flap 16 is removed. The canvas 12 is then folded over the flap so that the flap 16 is sandwiched along two sides and an edge by the canvas. The canvas 12 is held in position by the securing means 20 and the strip of adhesive tape 22. Then the flap 16 is forced downwardly towards the frame 1 1, thereby causing the canvas to stretch and become drum-tight without wrinkles. The aforementioned operation is repeated along all four flaps and then the flaps are held in juxtaposition to the back side of the frame 11 by staples or other mechanical securing means.

It will be obvious that depending upon the angular orientation of the flaps 16 relative to the frame 11, as shown in FIG. 4, the degree of tension to be applied to the canvas 12 can be carefully controlled and therefore canvasses of varying dimensions can be stretched and mounted by the stretcher means 10 without having to trim the canvas or change the dimensions of the stretcher means.

If desired, a cloth liner 23 can be disposed over the front side of the base 15 as shown in FIGS. 3 and 4, so that when the canvas is secured to the stretcher means 10 a complete framed, lined and stretched canvas will be produced.

An alternate embodiment of the present invention is illustrated in FIGS. 640, wherein in FIG. 6 the canvas 12 is shown with its truncated ends. The stretcher mechanism 30 of the alternate embodiment consists of a base 31, which is constructed from four wooden strips 32 having mitered complementary corner joints in order to form a rectangular base having an opening 37 when the strips 32 are joined aling their corner joints. Secured to the outer edges or periphery 33 of the base 31 is a securing means 34 which serves as a hinge and is shown for illustrative purposes to be two-sided adhesive tape. but can be constructed from any type of flexible material. A plurality of flaps 35, which have a substantially rectangular configuration with a beveled corner are secured to the base 31 by the securing means 34, as shown best in FIG. 7. The flaps 35 are initially positioned so that the beveled corner is disposed adjacent the lower outer edge of each of the strips 32 forming the base 31. When in this position the flaps 35 are in perpendicular orientation to the outer edges 33 of the base 31.

In assembly, the canvas 12 is laid on a flat surface with its painted side down. The stretcher mechanism 30 is positioned as shown in FIG. 6 and then set down on the back of the canvas as illustrated in FIG. 7. When the stretcher mechanism 30 is in position so that an equal portion of the canvas extends outwardly beyond each of the flaps 35, the canvas is wrapped over the flap as partially shown in FIG. 7, so that the canvas 12 is caused to adhere to the securing means 34. When all four flaps have been sandwiched by the canvas 12, the two opposing flaps 35 are pivoted upwardly towards the outer edges 33 of the base 31. Since the canvas 12 is held by the securing means 34 as the flaps 35 are pivoted as shown in FIG. 8, the canvas 12 is caused to be stretched, thereby becoming drum-tight across the opening 37 of the base 31. When the flaps 35 are pivoted into abutment with the outer edges 33, the canvas is caused to be held in sandwiched relationship between the securing means 34.

After the aforementioned assembly operation has been completed for two of the opposite flaps, the operations should be repeated with the remaining two flaps.

It will be noted from FIG. 9 that the outer edges 33 of the base 31 are beveled slightly inwardly so that when the flaps 35 are in a fully closed position the thickness of the canvas causes the flaps to be slightly set off from the outer edges, thereby causing the flaps to assume a vertical inclination. If it is desired to achieve a greater detail of tension upon the canvas, a simple method of accomplishing same is to incline the outer edges inwardly to a greater angle, thereby enabling the flaps to move through a greater segment of its arc and place additional stress upon the canvas.

H6. illustrates an additional alternate embodiment wherein mechanical fastening means 36, such as nails, are secured to the flaps 35 so that when the flaps are pivoted upwardly to cause the canvas 12 to be sandwiched between the flaps 35 and the outer edges 33 of the base 31, the mechanical fastening means 36 are caused to be driven into the base 31, thereby securely holding the flaps and canvas in abutting juxtaposition to the outer edges of the base.

For the purposes of exemplification, particular embodiments of the invention have been shown and de scribed according to the best present understanding thereof. However, it will be apparent that changes and modifications in the arrangement and construction of the parts, including the types of material utilized therein, may be resorted to without departing from the spirit and scope of the invention.

1 claim:

1. An assembly for stretching a canvas comprising:

a substantially rectangular base having an opening therein;

a plurality of flaps;

flexible means pivotally securing one of said flaps to each side of said base, said flaps extending outwardly away from the side of said base in spaced complementary relationship thereto;

means for (maintaining) securing said flaps to the sides of said base in complementary juxtaposition to the sides of said base, whereby a canvas secured to said flaps is maintained in a taut condition between said flaps and the sides of said base.

2. An assembly in accordance with claim I, wherein said flexible means and said securing means comprise an adhesive faced tape.

3. An assembly in accordance with claim 1, wherein said means for securing said flaps in complementary juxtaposition to the sides of said base comprises an adhesive faced tape.

4. An assembly in accordance with claim 1, wherein said means for maintaining said flaps in complementary juxtaposition to the sides of said base comprises a slender piece of metal having a pointed end for piercing said base.

a: u: a: 

1. An assembly for stretching a canvas comprising: a substantially rectangular base having an opening therein; a plurality of flaps; flexible means pivotally securing one of said flaps to each side of said base, said flaps extending outwardly away from the side of said base in spaced complementary relationship thereto; means for (maintaining) securing said flaps to the sides of said base in complementary juxtaposition to the sides of said base, whereby a canvas secured to said flaps is maintained in a taut condition between said flaps and the sides of said base.
 1. An assembly for stretching a canvas comprising: a substantially rectangular base having an opening therein; a plurality of flaps; flexible means pivotally securing one of said flaps to each side of said base, said flaps extending outwardly away from the side of said base in spaced complementary relationship thereto; means for (maintaining) securing said flaps to the sides of said base in complementary juxtaposition to the sides of said base, whereby a canvas secured to said flaps is maintained in a taut condition between said flaps and the sides of said base.
 2. An assembly in accordance with claim 1, wherein said flexible means and said securing means comprise an adhesive faced tape.
 3. An assembly in accordance with claim 1, wherein said means for Securing said flaps in complementary juxtaposition to the sides of said base comprises an adhesive faced tape. 